Reloader/docs/Reloader-vs-ConfigmapController.md

Reloader vs ConfigmapController

Reloader is inspired from Configmapcontroller but there are many ways in which it differs from configmapController. Below is the small comparison between these two controllers.

Reloader	ConfigmapController
Reloader on the other hand can watch and detect changes in both secrets and configmaps.
ConfigmapController can only watch changes in configmaps. It cannot detect changes in other resources like secrets.
Reloader on the other hand can perform rolling upgrades on deployments as well as on statefulsets and daemonsets	ConfigmapController can only perform rolling upgrades on deployments. It currently does not support rolling upgrades on statefulsets and daemonsets
Reloader provides both unit test cases and end to end integration test cases for future updates. So one can make sure that new changes do not break any older functionality.
Currently there are no unit test cases or end to end integration test cases in configmap controller. It add difficulties for any additional updates in configmap controller and one can not know for sure if new changes break any older functionality or not.
Reloader uses SHA1 to encode the change in configmap or secret. It then saves the SHA1 value in STAKATER_FOO_CONFIGMAP or STAKATER_FOO_SECRET environment variable depending upon where the change has happened. The use of SHA1 provides a concise 40 characters encoded value that is also very less pron to collision.	Configmap controller uses FABRICB_FOO_REVISION environment variable to store any change in configmap controller. It does not encode it or convert it in suitable hash value to avoid data pollution in deployment.